1. Field of the Invention
This invention relates to adhesives and the use of such adhesives for adhering a material to a substrate, for example, for adhering a carpet having an attached foam backing to a flooring substrate, one advantage of the adhesive being that it may readily be reactivated to permit removal of the adhering material from the substrate.
2. Description of the Prior Art
Many methods and adhesive materials are known in the prior art for the adhesion of a material to a substrate. A paper product may be adhered to a solid substrate, a wallpaper may be adhered to a plaster wall, a label may be adhered to a variety of solid substrates, a decorative item may be applied to a wall, a cupboard, or a metal panel such as in a car, or a foam backed carpet may be applied to a solid substrate, e.g. a concrete floor. The adhesive material used will depend on the particular material and substrate combination and the method of achieving the adhesion will vary from one particular use to another.
U.S. Pat. No. 3,704,197 teaches a removable carpet tile comprising a foam backed carpet and a water-dispersed acrylic adhesive with high tack applied with a figurated roller to the outer surface of the foam backing for adhesion of the carpet to a substrate, only 10 to 50% of the foam backing being treated with adhesive with the constraint that the peel strength of the adhesive is from 0.1 to 0.9 lbs/in and thereby less than the delamination strengh (1-2.25 lbs/in ) of the foam backing. Thus, the carpet may be removed from the flooring substrate without foam delamination. U.S. Pat. No. 3,847,647 teaches the process for applying this acrylic adhesive to the foam backing of a carpet. In U.S. Pat. No. 4,075,377 there is disclosed the use of a mesh installed between the foam backing of a carpet and the substrate so that when an adhesive is applied those areas of the foam backing covered by the mesh are not adhered to the substrate, thereby allowing the carpet and the mesh material to be peeled off subsequently without leaving gross quantities of the foam backing adhering to the flooring substrate. Peel strength for this arrangement is not disclosed.
Chemical Abstracts references 82:157249d and 92:112079p refer respectively to Japanese published patent applications Japenese Kokai Nos. 74/128,036 and 79/133,529 and teach that complete adhesion of the foam backing of a carpet to a flooring substrate is achieved using a mixture of a natural rubber latex having a low ammonia content and a talc. The peel strength of such an adhesive is rather low (about 0.1 lb/in) and allows subsequent peeling of the carpet from the flooring substrate without foam delamination.
Water re-moistenable adhesives are well known in the paper field, such as wallpaper, postage stamps, labels etc. as is documented in "Handbook of Adhesives", Chapter 46, Van Nostrand Reinhold, N.Y. 1977. The adhesive is coated on to, for example, a paper layer and dried. The adhesive is activated by contact with water allowing the product to be adhered to a substrate. The adhesive may be subsequently reactivated with water, thereby allowing the product to be separated from the substrate.
U.S. Pat. No. 4,098,944 teaches a mixture of carboxylated styrene-butadiene latex and hydrocarbon wax applied as a layer to the surface of a skinned but not fully dry latex foam rubber backed carpet. This coating imparts abrasion resistance to the latex foam rubber backing.